The image in this answer shows the effect of the new change which significantly decenters the core question/answer part of stack exchange in wider monitors. Notice how far left the Q/A is shifted, with the red indicating white space.
My suggestion (or bug report, depending on intent) is to keep the Q/A centered. My monitor is a widescreen and there is nearly twice as much white space on the right as compared to the left when you scroll down and look at answers further down the page.
This is disorienting and aesthetically really unpleasing.